David Wassarman, professor of cell and regenerative biology at the University of Wisconsin School of Medicine and Public Health, described flies as “humans with wings” at the McArdle Seminar in Cancer Biology Wednesday.

Bill Sugden, the seminar host, said there are 1.7 million cases of traumatic brain injury a year, which is the same as the number of new cancer cases, according to the Centers for Disease Control.

Wassarman defined traumatic brain injury as “damage to the brain caused by mechanical force.” The primary causes of traumatic brain injury are falls and car accidents, he said.

Wassarman said he distinguishes between two types of injuries: primary injuries and secondary injuries. Secondary injuries include cellular and molecular events, he said.

Traumatic brain injury causes physical problems, cognitive problems, behavioral problems and brain cell death, Wassarman said. He said flies are useful models to study the injuries because they have similar but simpler innate immune responses to humans.

An understanding of the flies’ immune response will lead to an understanding of these mechanisms in humans, he said.

Wassarman said he studies the secondary injuries, the cellular and molecular events that occur after the mechanical injury.

“We want to understand the fundamental aspects of TBI, and by using flies we can get at the fundamental cellular and molecular events that are occurring,” he said.

Flies are inexpensive to house and breed rapidly with a short life span, so they can be examined over their entire lifetime, Wassarman said. A variety of experimental tools like genetic screening can be used on flies, he said.

Wassarman constructed a device called high-impact trauma, which inflicts traumatic brain injury in flies. Flies are put in a vile and slammed against a hard surface, causing harm to multiple body parts including the brain, he said.

The team found traumatic brain injury causes temporary incapacitation, reduced lifespan, neurodegeneration, activation of the innate immune response and, in some cases, death.

The occurrence of death hinges on multiple factors including impact of force, age at the time of traumatic brain injury and genetic background, Wassarman said.

“Something is happening during the aging process, and if we can control that we can reduce the mortality from TBI,” he said.

Older flies have a higher rate of mortality compared to younger flies after traumatic brain injury, Wassarman said. Studies could reveal a reason to treat older people affected by traumatic brain injury differently from younger people, he said.

Wassarman believes that a fly’s genes affect the aging process, and in turn, the effects of traumatic brain injury, he said. He also found a correlation between extended lifespan and reduced death from traumatic brain injury.

The researchers also identified genetic risk factors for traumatic brain injuries. Wasserman said this discovery could allow children and young adults with certain genes to be warned not to play football or high-risk sports using genetic testing.

“I’m hoping that what we are doing with flies will lead to new therapies in humans,” Wassarman said.